Question

What is the molarity of a 250.0 milliliter aqueous solution of sodium hydroxide that contains 15.5 grams of solute? 6.2 M

Answer 1

Moles = 15.5 g / 40 g/mol = 0.3875 mol

M = 0.3875 mol / 0.250 L = 1.55M

Answer 2

Answer : The molarity is 1.55 M

Explanation :

Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.

Formula used :

$\text{Molarity}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

or,

$\text{Molarity}=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (in L)}}$

In this question the solute is, sodium hydroxide.

Now put all the given values in this formula, we get:

$\text{Molarity}=\frac{15.5g\times 1000}{40g/mole\times 250.0L}$

$\text{Molarity}=1.55mole/L=1.55M$

Therefore, the molarity is 1.55 M